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排序方式: 共有1512条查询结果,搜索用时 13 毫秒
51.
Richard Lakerveld Herman J.M. Kramer Andrzej I. Stankiewicz Johan Grievink 《Chemical Engineering and Processing: Process Intensification》2010
The design of current industrial crystallizers is strongly focussed on optimization of known types of crystallization equipment. These crystallizers harbour various physical phenomena, which are strongly entangled. The application of generic principles of process intensification (PI) to crystallization processes requires individual control over physical phenomena. A new design method is applied that exploits elementary processing functions as building blocks for design instead of existing equipment, which enables the application of generic principles of PI. Innovations in the field of crystallization to manipulate shear forces, manipulate nucleation rates with external fields, and improve control over solvent removal with membranes are key technologies. A case study demonstrates the application of task-based design for solution crystallization. The results show how task-based design leads to high modularization of the process representation and model architecture. In addition, task-based design enables the application of generic PI principles, which results in a large flexibility to manipulate final product quality. Future needs include generalization of task-based design for crystallization and development of novel technologies for single task manipulation. 相似文献
52.
Marcos Rodriguez Pascual Daniela Trambitas Elisa Saez Calvo Herman Kramer Geert-jan Witkamp 《Chemical Engineering Research and Design》2010
A crystallizer was built and a procedure developed to accurately measure the eutectic solubility lines where ice and salt coexist in equilibrium with the solution, for potential application of Eutectic Freeze Crystallization. The eutectic solubility lines of the ternary system NaHCO3–Na2CO3–H2O were determined experimentally and calculated with the extended UNIQUAC model. The extended UNIQUAC model describes the experimental data quite well. Anhydrous NaHCO3 and Na2CO3·10H2O were the only two types of crystals present in equilibrium with ice crystals in the ternary system. At the quadruple point NaHCO3 and Na2CO3·10H2O are in equilibrium with a solution of about 4.34 wt% of Na2CO3 and 4.77 wt% of NaHCO3 at −3.32 °C. The anhydrous NaHCO3 crystals were needle shaped with lengths between 5 and 10 μm, that were agglomerated into particles of about 100–300 μm, while the Na2CO3·10H2O crystals were hexagonally shaped with sizes between 100 and 500 μm. 相似文献
53.
Continuous operation of membrane bioreactor treating toluene vapors by Burkholderia vietnamiensis G4
Amit Kumar Jo Dewulf Munkhtsetseg Luvsanjamba Herman Van Langenhove 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2008,140(1-3):193-200
A laboratory-scale biofilm membrane bioreactor inoculated with Burkholderia vietnamiensis G4 was examined to treat toluene vapors in a waste gas stream. The gas feed side and nutrient solution were separated by a composite membrane consisting of a porous polyacrylonitrile (PAN) support layer coated with a very thin (0.3 μm) dense polydimethylsiloxane (PDMS) top layer. After inoculation, a biofilm developed on the dense layer. The biofilm membrane bioreactor was operated continuously at different residence times (28–2 s) and loading rates (1.2–26.7 kg m−3 d−1), with inlet toluene concentrations ranging from 0.21 to 4.1 g m−3. The overall performance of the membrane bioreactor was evaluated over a period of 165 days. Removal efficiencies ranging from 78% to 99% and elimination capacities from 4.2 to 14.4 kg m−3 d−1 were observed after start-up period depending on the mode of operation. A maximum elimination capacity of 14.4 kg m−3 d−1 was observed at a loading rate of 17.4 kg m−3 d−1. Overall, the results illustrate that biofilm membrane reactors can potentially be more effective than conventional biofilters and biotrickling filters for the treatment of air pollutants such as toluene. 相似文献
54.
Thomas C. van den Ende Jeroen M. M. Heuts Dr. Geoffroy P. P. Gential Marten Visser Michel J. van de Graaff Dr. Nataschja I. Ho Prof. Dr. Wim Jiskoot Dr. A. Rob P. M. Valentijn Nico J. Meeuwenoord Prof. Dr. Herman S. Overkleeft Prof. Dr. Jeroen D. C. Codée Prof. Dr. Sjoerd H. van der Burg Dr. Els M. E. Verdegaal Prof. Dr. Gijsbert A. van der Marel Prof. Dr. Ferry Ossendorp Dr. Dmitri V. Filippov 《Chembiochem : a European journal of chemical biology》2021,22(7):1215-1222
Synthetic vaccines, based on antigenic peptides that comprise MHC−I and MHC-II T-cell epitopes expressed by tumors, show great promise for the immunotherapy of cancer. For optimal immunogenicity, the synthetic peptides (SPs) should be adjuvanted with suitable immunostimulatory additives. Previously, we have shown that improved immunogenicity in vivo is obtained with vaccine modalities in which an SP is covalently connected to an adjuvanting moiety, typically a ligand to Toll-like receptor 2 (TLR2). SPs were covalently attached to UPam, which is a derivative of the classic TLR2 ligand Pam3CysSK4. A disadvantage of the triply palmitoylated UPam is its high lipophilicity, which precludes universal adoption of this adjuvant for covalent modification of various antigenic peptides as it renders the synthetic vaccine insoluble in several cases. Here, we report a novel conjugatable TLR2 ligand, mini-UPam, which contains only one palmitoyl chain, rather than three, and therefore has less impact on the solubility and other physicochemical properties of a synthetic peptide. In this study, we used SPs that contain the clinically relevant neoepitopes identified in a melanoma patient who completely recovered after T-cell therapy. Homogeneous mini-UPam-SP conjugates have been prepared in good yields by stepwise solid-phase synthesis that employed a mini-UPam building block pre-prepared in solution and the standard set of Fmoc-amino acids. The immunogenicity of the novel mini-UPam-SP conjugates was demonstrated by using the cancer patient's T-cells. 相似文献
55.
Stability of lead(II) complexes of alginate oligomers 总被引:1,自引:0,他引:1
Davis TA Pinheiro JP Grasdalen H Smidsrød O van Leeuwen HP 《Environmental science & technology》2008,42(5):1673-1679
The current work reports on the Pb(ll) complexes formed with oligomeric uronic acids (carboxylated saccharide residues) found polymerized in the cell walls and envelopes of algae and bacteria alike. The application of partial acid hydrolysis, size-exclusion chromatography (SEC), 1H NMR, and scanned deposition stripping chronopotentiometry (SSCP) has permitted the determination of stability constants for Pb(II) with both mannuronic (M) and guluronic (G) acid oligomers ranging from the dimer to the pentamer. The determined logarithm of the stability constants range between 4.11 +/- 0.05 and 5.00 +/- 0.04 mol(-1) x dm3 for the eight oligomers studied (pH 6; I = 0.1 mol x dm(-3)). Additional experiments under the same experimental conditions employing galacturonic and glucuronic acid oligomers yielded slightly lower values (2.19 +/- 0.10 to 4.02 +/- 0.07 mol(-1) x dm3) that were expected based on their structure, whereby the monomers which were not included in the alginate oligomer series (unavailable by SEC), yielded the lowest stability constants. This work demonstrates the applicability of the SSCP technique for the determination of stability constants for metal-ligand complexes in which the ligands display relatively low molecular mass. Previous studies on heavy metal interaction with the matrix polysaccharide alginate have largely been restricted to the whole polymer that forms a gel upon binding to network bridging ions such as calcium. The results will be discussed in this context with the emphasis being placed on the relevance of these findings to processes occurring at the biointerface and results from the relevant literature. 相似文献
56.
市场预期未来几年石油供应将继续保持偏紧状态,世界石油市场正在经历20世纪80年代中期以来最大、最持久的结构性变化。 相似文献
57.
Fanhua Ma Jiao DengZhengliang Qi Shun LiRenzhe Chen Herman YangShuli Zhao 《International Journal of Hydrogen Energy》2011,36(15):9278-9285
A quasi-dimensional model has been developed for an SI engine fuelled with natural gas/hydrogen blends, the combustion chamber was divided into two zones by the flame front, and a turbulent entrainment combustion model was conducted. This paper investigates the effects of calibration coefficients on the model, which includes the turbulence intensity coefficient C2, the Taylor length scale coefficient C3, and the Ignition lag coefficient Cig. Validation by experiments is carried out under various operating conditions including different ignition timing, excess air ratio, manifold ambient pressure (MAP) and fraction of hydrogen enrichment. The results show that Cig always stay the same at 1.52. When the fuel is pure natural gas, C3 plays an important role in the simulation which changes from 0.95 to 2. The main factor changes from C3 to C2 when the hydrogen fraction increases from 30% to 55%. When the engine is fuelled by pure hydrogen C2 to changes from 1.65 to 2.1. 相似文献
58.
Daniella Regina Mulinari Herman J.C. Voorwald Maria Odila H. Cioffi Maria Lúcia C.P. da Silva Tessie Gouvêa da Cruz Clodoaldo Saron 《Composites Science and Technology》2009
Natural fibers used in this study were both pre-treated and modified residues from sugarcane bagasse. Polymer of high density polyethylene (HDPE) was employed as matrix in to composites, which were produced by mixing high density polyethylene with cellulose (10%) and Cell/ZrO2·nH2O (10%), using an extruder and hydraulic press. Tensile tests showed that the Cell/ZrO2·nH2O (10%)/HDPE composites present better tensile strength than cellulose (10%)/HDPE composites. Cellulose agglomerations were responsible for poor adhesion between fiber and matrix in cellulose (10%)/HDPE composites. HDPE/natural fibers composites showed also lower tensile strength in comparison to the polymer. The increase in Young’s modulus is associated to fibers reinforcement. SEM analysis showed that the cellulose fibers insertion in the matrix caused an increase of defects, which were reduced when modified cellulose fibers were used. 相似文献
59.